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Five-Year Longitudinal Assessment of the Prognosis of Apical Microsurgery

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  1. 1. Clinical ResearchFive-Year Longitudinal Assessment of the Prognosisof Apical MicrosurgeryThomas von Arx, DMD,* Simon S. Jensen, DDS,*† Stefan H€ nni, DMD,‡ aand Shimon Friedman, DMD§AbstractIntroduction: Apical surgery is an important treatment Key Wordsoption for teeth with post-treatment apical periodon- Apical surgery, long-term study, outcome, predictors, prognostic factorstitis. Knowledge of the long-term prognosis is necessarywhen weighing apical surgery against alternative treat-ments. This study assessed the 5-year outcome of apicalsurgery and its predictors in a cohort for which the A pical surgery is an important endodontic treatment modality intended to cure persistent apical periodontitis (AP) after orthograde root canal treatment. Post-treatment AP has been shown to affect up to 65% of root-filled teeth in different1-year outcome was previously reported. Methods: populations (1). This highly prevalent condition is preferably treated by orthogradeApical microsurgery procedures were uniformly per- (nonsurgical) retreatment; however, specific benefit-risk analysis or patientformed using SuperEBA (Staident International, Staines, preference may favor apical surgery as the treatment of choice (2). As an alternativeUK) or mineral trioxide aggregate (MTA) (ProRoot MTA; to nonsurgical or surgical retreatment, the tooth can be extracted and replaced withDentsply Tulsa Dental Specialties, Tulsa, OK) root-end an implant-supported restoration, with a tooth-borne fixed prosthesis, or with afillings or alternatively Retroplast capping (Retroplast removable prosthesis (3). Thus, for teeth with post-treatment AP, patients currentlyTrading, Rorvig, Denmark). Subjects examined at can select from 3 contrasting treatment options. A critical consideration in this1 year (n = 191) were invited for the 5-year clinical challenging decision juncture is the prognosis, as suggested by the current bestand radiographic examination. Based on blinded, in- evidence for each treatment option. This study addressed the outcome of apicaldependent assessment by 3 calibrated examiners, the surgery.dichotomous outcome (healed or nonhealed) was deter- Over the years, over 75 studies have reported a very wide range of data on themined and associated with patient-, tooth-, and prognosis of apical surgery using a variety of root-end filling materials and surgicaltreatment-related variables using logistic regression. techniques (4). Attempts to narrow the range of the reported outcomes by selectingResults: At the 5-year follow-up, 9 of 191 teeth were studies based on methodological rigor and to identify significant outcome predictorsunavailable, 12 of 191 teeth were extracted, and 170 have been reported (4, 5). In a recent systematic review and meta-analysis, Setzerof 191 teeth were examined (87.6% recall rate). A total et al (6) concluded that the prognosis of ‘‘endodontic microsurgery’’ including theof 129 of 170 teeth were healed (75.9%) compared with use of high-power illumination and magnification (microscope or endoscope);83.8% at 1 year, and 85.3% were asymptomatic. Two ultrasonic tips for root-end cavity preparation; and mineral trioxide aggregatesignificant outcome predictors were identified: the (MTA), intermediate restorative material, or SuperEBA for root-end filling is signif-mesial-distal bone level at #3 mm versus >3 mm icantly better than that of the ‘‘traditional root-end surgery’’ performed in many offrom the cementoenamel junction (78.2% vs 52.9% the studies. The reviewers suggest a 94% chance to cure post-treatment AP afterhealed, respectively; odds ratio = 5.10; confidence endodontic microsurgery (6); however, this conclusion is supported exclusivelyinterval, 1.67-16.21; P < .02) and root-end fillings by short-term (1 or 2 years) outcome reports. Considering the 5% to 25% riskwith ProRoot MTA versus SuperEBA (86.4% vs. 67.3% of regression to AP reported beyond 3 or more years after apical surgeryhealed, respectively; odds ratio = 7.65; confidence (7–12), the short-term data supporting the current systematic review’s conclusionsinterval, 2.60-25.27; P < .004). Conclusions: This study (6) may overestimate the long-term prognosis of endodontic microsurgery (4).suggested that the 5-year prognosis after apical micro- Similarly, the assessment of significant outcome predictors requires long-termsurgery was 8% poorer than assessed at 1 year. It observations as reported in only 4 studies (12–15), none of which focused onalso suggested that the prognosis was significantly endodontic microsurgery. By reviewing the contrasting results of these 4 studiesimpacted by the interproximal bone levels at the and the recent reviews, the potential significant predictors of healing after apicaltreated tooth and by the type of root-end filling material surgery may be patient related (patient’s age over 45 years), tooth related (theused. (J Endod 2012;38:570–579) absence of preoperative signs and symptoms, adequate root filling density, From the *Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland; †Department of Oral and MaxillofacialSurgery, Copenhagen University Hospital, Copenhagen, Denmark; ‡Private Practice, Bern, Switzerland; and §Discipline of Endodontics, Faculty of Dentistry, University ofToronto, Toronto, Ontario, Canada. Address requests for reprints to Dr Thomas von Arx, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Freiburgstrasse 7,CH-3010 Bern, Switzerland. E-mail address: thomas.vonarx@zmk.unibe.ch0099-2399/$ - see front matter Copyright ª 2012 American Association of Endodontists.doi:10.1016/j.joen.2012.02.002570 von Arx et al. JOE — Volume 38, Number 5, May 2012
  2. 2. Clinical Researchinadequate root filling length, a small periapical lesion of #5 mm, The entire cohort of 191 subjects attending the 1-year examinationand the absence of a post), and treatment related (use of the was accounted for at the 5-year juncture. Teeth that had been extractedmicrosurgical technique) (5, 12–15). were recorded along with the diagnosis at the time of extraction. All To further elucidate the prognosis of apical microsurgery and the subjects who did not respond, declined examination, or could not beoutcome predictors, the purpose of this prospective longitudinal study reached were considered lost to follow-up.was to provide evidence for the 5-year outcome of apical microsurgery The treatment provider performed all follow-up examinations. Toin a cohort of patients for whom we previously reported the 1-year minimize bias, the examination and data entry were performed blindedoutcome (16). Furthermore, patient-, tooth-, and treatment-related of the subject’s pre- and postoperative data. Subjects were askedvariables were investigated for their outcome-predicting value to to report occurrences of pain. The clinical examination recorded theprovide clinicians with the ability to project the particular prognosis presence or absence of swelling and sinus tract and the response tofor specific patients who consider apical microsurgery versus alterna- percussion and palpation. Radiographs were exposed using thetive options. paralleling technique with the use of the XCP Rinn film holder (Dentsply Rinn, Elgin, IL) to assess the periapical status. Materials and Methods The study cohort and interventions were characterized previously Outcome Assessment(16); however, key characteristics and details not provided previously Outcome was assessed based on clinical and radiographicare described herein to satisfy the requirement of adequate reporting. measures. Radiographs were interpreted independently by 2 examiners (S.H. and S.S.J.) and by the treatment provider who wereStudy Cohort all previously calibrated for use of the healing classification described Subjects were recruited from among 251 patients who received by Molven et al (17). Calibration included the radiographic assessmentapical surgery at the Department of Oral Surgery and Stomatology, of sample cases using the schematic depiction of the healing categoriesSchool of Dental Medicine, University of Bern, Bern, Switzerland, (17). Intra- and interexaminer agreement was assessed using the Cohenfrom January 2000 to December 2003. A total of 194 teeth in the kappa statistics.same number of subjects met the inclusion criteria (16) and were The radiographic evidence of periapical healing was classifiedenrolled in the study. This cohort is characterized for key patient- as complete (Fig. 1), incomplete (scar tissue formation, Fig. 2),and tooth-related preoperative variables in Table 1. uncertain (Fig. 3), or unsatisfactory (Fig. 4) in strict adherence to well-established universal criteria (17, 18). Interpretation conflictsIntervention were resolved by reaching consensus among the 3 examiners. To One oral surgeon (T.v.A.) who has extensive experience in per- ascertain that all allocations to the ‘‘incomplete healing’’ categoryforming apical microsurgery provided all treatments. The surgical were appropriate, the teeth in this category underwent additionaltechnique was previously described in detail (16). Briefly, local anes- independent scrutiny by a fourth examiner (S.F.).thesia was administered; full-thickness mucoperiosteal flap elevated; With the tooth considered as the evaluated unit and mul-osteotomy performed; the apical 3 mm of the root resected with no tirooted teeth classified according to the worst-appearing root, theor minimal bevel; the pathological tissue curetted; hemostasis estab- outcome was defined by combining the clinical and radiographiclished; and the root end inspected with a rigid endoscope for accessory measures (19). Teeth were classified as ‘‘healed’’ when presentingcanals, isthmus, and cracks. Two methods of root-end management with complete or incomplete healing without clinical signs andwere used without randomized allocation: (1) a root-end cavity was symptoms. Teeth were classified as ‘‘not healed’’ when presentingprepared with sonic microtips (Kavo Dental, Biberach, Germany) with uncertain or unsatisfactory healing or with clinical signs or symp-and filled with either SuperEBA (Staident International, Staines, UK) toms regardless of the radiographic appearance. In addition to thein 55 subjects (28.4%) or with ProRoot MTA (Dentsply Tulsa Dental healing outcome, teeth were classified as ‘‘functional’’ based on theSpecialities, Tulsa, OK) in 53 subjects (27.3%) and (2) a shallow absence of clinical signs and symptoms regardless of the radiographicconcavity was drilled into the root end and sealed with a resin appearance.composite (Retroplast; Retroplast Trading, Rorvig, Denmark) bondedwith Gluma (Heraeus Kulzer, Dormagen, Germany) in the remaining 86 Statistical Analysissubjects (44.3%). Flaps were secured with interrupted sutures (Sera- Percent frequencies were generated to characterize the studylon; Serrag-Wiessner, Nalla, Germany). Nonsteroidal analgesics and material in regards to 14 independent variables: patient relateda 0.12% chlorhexidine-digluconate mouthwash were prescribed (ie, age, sex, and smoking), tooth related (ie, tooth type, pain, clinicalroutinely, whereas prophylactic antibiotics were prescribed for 61% signs/symptoms [tenderness to palpation or percussion, swelling, andof subjects. The main indications for antimicrobial prophylaxis sinus tract], size of periapical lesion, interproximal bone level, apicalincluded a history of acute infection, the presence of clinical signs extent of root canal filling, post, and previous apical surgery), and treat-and symptoms at the preoperative examination, and an anticipated ment related (ie, antibiotic prescription, root-end filling material, andduration of surgery longer than 1 hour. initial postoperative healing). Interexaminer agreement was assessed with the Cohen weightedFollow-up Examination kappa statistics. All statistical analyses were performed with the software At the 1-year follow-up examination, subjects were advised that R version 2.12.2 (The R Foundation for Statistical Computing, Vienna,they would be contacted 4 years later for an additional clinical Austria). The dependent variable, the dichotomous outcome (healed vsand radiographic examination of the surgically treated teeth. With nonhealed), was assessed for associations with all 14 measured in-3 subjects lost to follow-up at the 1-year examination (16), a total of dependent variables using multivariate analysis. Logistic regression191 subjects were invited by letter to attend the 5-year examination. models were constructed to identify significant outcome predictorsThose subjects who did not respond were contacted by telephone while accounting for confounding associations and extraneous vari-and encouraged to attend without an offer of reimbursement. ables. Significance was established at the 5% level. Because of theJOE — Volume 38, Number 5, May 2012 5-Year Outcome of Apical Surgery 571
  3. 3. Clinical ResearchTABLE 1. Preoperative Characteristics of the Inception Cohort (n = 194) and the Healed Outcome at 1 Year (n = 191) and 5 Years (n = 170) after ApicalMicrosurgery Related to Potential Outcome Predictors Inception cohort 1-year follow-up 5-year follow-up Variable n %n n Healed % healed n Healed % healed Total 194 100 191 160 83.8 170 129 75.9 Age <45 years 60 30.9 60 54 90.0 56 44 78.6 $45 years 134 69.1 131 106 80.9 114 85 74.6 Sex Male 86 44.3 85 68 80.0 76 54 71.1 Female 108 55.7 106 92 86.8 94 75 79.8 Smoking No 141 72.7 139 116 83.5 123 97 78.9 Yes 53 27.3 52 44 84.6 47 32 68.1 Teeth Maxilla anteriors 55 28.4 54 46 85.2 52 43 82.7 Premolars 43 22.2 42 35 83.3 34 27 79.4 Molars 25 12.9 24 22 91.7 23 16 69.6 Mandible anteriors 6 3.1 6 6 100 2 1 50.0 Premolars 13 6.7 13 10 76.9 12 10 83.3 Molars 52 26.8 52 41 78.8 47 32 68.1 Pain Absent 111 57.2 109 97 89.0 98 76 77.6 Present 83 42.8 82 63 76.8 72 53 73.6 Signs Absent 116 59.8 114 101 88.6 103 77 74.8 Tender to percussion 30 15.5 30 25 83.3 23 19 82.6 Swelling, sinus tract 48 24.7 47 34 72.3 44 33 75.0 Lesion size No lesion 17 8.8 17 16 94.1 16 14 87.5 #5 mm 106 54.6 104 90 86.5 91 74 81.3 >5 mm 71 36.6 70 54 77.1 63 41 65.1 Crestal bone level* Mesial and distal #3 mm 150 77.3 148 123 83.1 133 104 78.2 Mesial or distal >3 mm 24 12.4 24 21 87.5 20 16 80.0 Mesial and distal >3 mm 20 10.3 19 16 84.2 17 9 52.9 Apical extent of root canal filling 0-2 mm short of apex 126 64.9 123 103 83.7 108 84 77.8 >2 mm short of apex 44 22.7 44 39 88.6 41 30 73.2 Beyond the apex 24 12.4 24 18 75.0 21 15 71.4 Post Absent 64 33.0 63 53 84.1 53 41 77.4 Present 130 67.0 128 107 83.6 117 88 75.2 Previous surgery No 176 90.7 173 146 84.4 154 118 76.6 Yes 18 9.3 18 14 77.8 16 11 68.8 Antibiotics Not prescribed 72 64 88.9 62 51 82.3 Prescribed 119 96 80.7 108 78 72.2 Root-end filling SuperEBA 55 42 76.4 49 33 67.3 ProRoot MTA 51 46 90.2 44 38 86.4 Retroplast 85 72 84.7 77 58 75.3 Postoperative healing Uneventful 174 148 85.1 156 120 76.9 Complication 17 12 70.6 14 9 64.3*Measured on radiographs from the cementoenamel junction or, if not visible, from the margin of a crown or filling.exploratory type of the study, no P value correction for multiple unrelated to the surgical treatment performed. Three subjects (1.5%)comparisons was performed. could not be reached, 6 subjects (3.1%) did not respond, and 3 subjects (1.5%) did not attend the 1-year examination. The total loss Results to follow-up from baseline to 5 years was 24 subjects (12.4%) including Attrition of the cohort at the 5-year follow-up examination is the extracted teeth.summarized in Table 2. A total of 170 of 194 subjects (87.6%) withthe same number of treated teeth were available for re-examination after Interexaminer Agreement5 years. Information was available for an additional 12 teeth (6.2%) that Kappa values of pair-wise comparisons among the 3were extracted because of fracture or prosthetic considerations examiners with regard to radiographic healing classification ranged572 von Arx et al. JOE — Volume 38, Number 5, May 2012
  4. 4. Clinical ResearchFigure 1. Mandibular first molar radiographically assessed as ‘‘complete healing’’ 5 years after apical microsurgery with ProRoot MTA root-end filling. (A) Preop-erative and (B) postoperative: in the mesial root, both canals and the isthmus were prepared and filled, whereas in the distal root 1 canal was prepared and filled.(C) The 1-year follow-up and (D) the 5-year follow-up.from 0.59 to 0.74, indicating fair to good agreement. A good to excellent uncertain/unsatisfactory healing was lowest in teeth treated withagreement was observed between each examiner’s classification ProRoot MTA.and the consensus classification, with kappa values ranging from0.74 to 0.92. Outcome Predictors The following variables were associated with healed rate dif-Outcome ferences of 10% or larger (considered clinically meaningful) at 5 years: Five years after apical microsurgery, 129 of 170 teeth (75.9%) 1. Patient related: smoking statuswere classified as healed compared with 83.8% at 1 year after treatment. 2. Tooth related: the type of tooth, the size of the lesion, and the crestalTaking into account the absence of clinical signs or symptoms, 145 of bone level170 teeth (85.3%) were classified as ‘‘functional’’ 5 years after apical 3. Treatment related: the type of root-end filling material, antibioticsurgery. Distribution of the radiographic classification categories for treatment, and the postoperative healing coursethe 170 teeth examined at 5 years is summarized in Table 3. Of 141 teethclassified as complete/incomplete healing at 1 year, 125 teeth (88.7%) The final logistic regression model revealed 1 tooth-related and 1remained so at 5 years, whereas 16 teeth (11.3%) regressed to uncer- treatment-related statistically significant predictor of a healed outcome:tain /unsatisfactory healing at 5 years. Conversely, of 29 teeth classified mesial-distal crestal bone level at #3 mm versus >3 mm from theas uncertain/unsatisfactory healing at 1 year, 5 teeth (17.2%) pro- cementoenamel junction (78.2% vs 52.9% healed, respectively; oddsgressed to complete/incomplete healing. On balance, the number of ratio = 5.10; confidence interval, 1.67–16.21; P < .02) and root-endteeth classified as complete/incomplete healing decreased from 141 fillings with ProRoot MTA versus SuperEBA (86.4% vs 67.3% healed,teeth at 1 year to 130 teeth at 5 years after treatment, a reduction respectively; odds ratio = 7.65; confidence interval, 2.60–25.27;of 7.8%. With regard to root-end filling materials, regression to P < .004; Tables 1 and 4).JOE — Volume 38, Number 5, May 2012 5-Year Outcome of Apical Surgery 573
  5. 5. Clinical ResearchFigure 2. The maxillary lateral incisor radiographically assessed as ‘‘incomplete healing’’ 5 years after apical microsurgery with ProRoot MTA root-end filling.(A) Preoperative, (B) postoperative, (C) 1-year follow-up, and (D) 5-year follow-up. Discussion follow-up reported in other relatively current apical surgery studies This prospective longitudinal study evaluated the 5-year prognosis with comparable observation periods (8, 10–12, 14, 15, 20). Theof apical microsurgery in a cohort for whom the 1-year data have been 88% recall rate achieved was consistent with the requirement forreported previously (16). The study design was consistent with the the second highest level of evidence (1b) for the assessment ofmethodology requirements for the assessment of prognosis at a high prognosis (21). Only 1 tooth per subject was included and consideredlevel of evidence. The study cohort was recruited, treated, and the unit of evaluation, and teeth presenting with through-and-through orfollowed-up prospectively, with data reported for subjects attending apicomarginal lesions were excluded to ascertain uniformity of theboth the 1-year (16) and 5-year examinations. The roughly 12% attri- cohort and to avoid potential confounding of the results. Patient- andtion of the inception cohort was lower than the 22% to 49% loss to tooth-related data collection followed a detailed protocol; however,574 von Arx et al. JOE — Volume 38, Number 5, May 2012
  6. 6. Clinical ResearchFigure 3. The mandibular first molar radiographically assessed as ‘‘uncertain healing’’ 5 years after apical microsurgery with Retroplast root-end capping.(A) Preoperative and (B) postoperative: both resected root faces were sealed including an isthmus in the mesial root. (C) The 1-year follow-up and (D) the5-year follow-up.the inception cohort was not characterized in regards to AP persisting Different patient-, tooth-, and treatment-related variables wereafter the initial treatment only or after retreatment as would have been explored for association with the outcome, and significant outcomedesired (4). Although the prognosis of apical surgery was better when predictors were identified using a multivariate analysis. Because thisAP persisted after retreatment than after initial treatment in 1 study (22), study followed up the cohort for whom the 1-year data were available,this variable was not a significant outcome predictor in another no sample size calculation was performed, and no specific sample sizestudy (15). target was set. To standardize interventions, 1 provider treated all subjects, and The overall 5-year healed rate of 76% (129/170 subjects)all teeth were root-end filled following a uniform surgical protocol. compared well with the 4- to 10-year healed rate of 74% reported inBecause the root-end filling techniques were not randomly allocated, the Toronto Study (15). In that study, not all subjects were treated usingthe level of evidence for comparing their effectiveness was lower the apical microsurgical technique, and 84% of teeth were root-end(2b) than would be provided by a randomized controlled trial (21). filled with ProRoot MTA, intermediate restorative material, or SuperEBA To ascertain objective outcome assessment, 2 independent exam- without a significant difference in outcome (15). In current years, onlyiners and the treatment provider interpreted the radiographic images a few apical surgery studies assessed the outcomes of 4 years or longerblinded to the preoperative appearance. Blinding of root-end filling (10–15, 20, 22, 23), whereas there have been many short-term studiesmaterials was not entirely possible because of the different radiographic (4). Especially in the past decade, many studies have reported onappearance of the 3 materials used. Stents were not manufactured to the outcome of apical microsurgery (6), albeit with only short-termfacilitate reproducible radiographic exposures, as was the case in the (#2 years) follow-up. Short-term observation after apical surgerymajority of apical surgery outcome studies; nevertheless, radiographs may overestimate the prognosis (4) because 5% to 25% of teeth re-were positioned with a film holder, and the paralleling exposure corded as healed at the short-term have been reported to regresstechnique was used to reduce distortion. when observed 3 years or longer after surgery (7–12). In theJOE — Volume 38, Number 5, May 2012 5-Year Outcome of Apical Surgery 575
  7. 7. Clinical ResearchFigure 4. The mandibular first molar radiographically assessed as ‘‘unsatisfactory healing’’ 5 years after apical microsurgery with Retroplast root-end capping. (A)Preoperative and (B) postoperative: the resected root face of the mesial root was sealed including the isthmus. (C) The 1-year follow-up and (D) the 5-year follow-up.present apical microsurgery study, regression occurred in perspective, the supporting bone level should be assessed preopera-approximately 11% of teeth assessed as healed at 1 year. This tively and carefully considered before the tooth is subjected to apicalregression was partially offset by fewer teeth that were healed at 5 microsurgery (24).years but not at 1 year. The overall healed rate 5 years after apical Although not a randomized controlled trial, this 5-year studymicrosurgery was 8% lower than it was after 1 year, underlining the offered an opportunity to examine the effectiveness of the 3 root-endoverestimated prognosis suggested by short-term studies on apical filling materials; ProRoot MTA (86% healed) was shown to be superiormicrosurgery (4). to SuperEBA (67% healed). Several shorter-term apical microsurgery One tooth-related variable was identified as an outcome studies have reported high success rates using ProRoot MTA rangingpredictor for which the prospective study design provided a high level from 89% to 97% (16, 20, 24, 25, 27–30). Three of these studiesof evidence (1b). Teeth that presented with no or minor interprox- (24, 27, 29) contributed to the conclusion in the recent systematicimal bone loss both mesially and distally had a higher healed rate review that the success rate of apical microsurgery was 94.5% (6).than teeth with greater interproximal bone loss (78% vs 53%, respec- In the present study, ProRoot MTA-treated teeth showed the leasttively). This finding corroborated the previously reported adverse regression at 5 years (just under 4%), suggesting the most effectiveeffect of compromised bone support on the prognosis after apical seal over the longer observation period. Of the teeth treated withsurgery (4, 24, 25). The risk, especially in the longer-term, is that ProRoot MTA, 86% were healed at 5 years. In the absence of any otheran apicomarginal bacterial pathway may develop over time when comparable long-term studies, our results suggested that, at best, thethe crestal bone level is already compromised at the time of apical chance of teeth to heal in the longer-term after apical microsurgerymicrosurgery (24). Such communication may not only compromise using ProRoot MTA would be 86%, which is lower than the 94% sug-periapical healing, but it can also lead to a significant loss of peri- gested in the recent systematic review (6). This suggested prognosisodontal attachment in the long-term, as observed in teeth that did is far better than that reported in previous 4-year or longer studiesnot heal after apical microsurgery (26). Therefore, from the clinical on apical surgery performed with other root-end filling materials and576 von Arx et al. JOE — Volume 38, Number 5, May 2012
  8. 8. Clinical ResearchTABLE 2. Distribution of the Study from Inception to the 5-Year Follow-up between the root canal and periapical tissues (31), the application of Retroplast is highly technique sensitive. Possibly, contamination of Population Subjects Status the resected root surface or trimming of excess material in some cases Inception cohort 194 Received treatment may compromise the seal and the prognosis. Lost to follow-up at 3 Did not attend 1-year examination Teeth root ends filled with SuperEBA showed the lowest healed Eligible for 5-year 191 Invited for examination rate (ie, 67%) 5 years after apical microsurgery, which is significantly follow-up lower than for ProRoot MTA-treated teeth. This 5-year prognosis was Lost to follow-up 9 1 deceased 10% better than reported in a previous 3-year study (36) but about at 5 years 2 left country 20% poorer than reported in 2 other long-term studies using SuperEBA 6 did not respond Teeth extracted 12 11 vertical fracture (23, 37). However, methodological issues, such as the use of the root as 1 prosthetic considerations the evaluated unit in both studies (23, 37) and a large loss to follow-up Attended 5-year 170 Teeth examined (37), precluded direct comparisons of our results with those of the examination previous studies (4). Of the 76% SuperEBA-treated teeth that were healed after 1 year in our previous study (16), 9% showed regression after 5 years in the current study, which is similar to the 8.5% regressionwithout emphasis on the microsurgical technique (8, 9, 11, 12, 13, 23). reported 5 to 7 years after apical microsurgery (10). Again, the highNevertheless, additional long-term, methodologically sound studies are short-term success rates of up to 97% reported using SuperEBArequired to augment the evidence for the prognosis after apical micro- (6, 16, 37, 20–22, 24) misrepresents the longer-term prognosis.surgery using ProRoot MTA. Taking into account the absence of clinical signs or symptoms, Of the Retroplast-treated teeth in this study, about 75% were 85% (145/170) of the teeth were ‘‘functional’’ 5 years after apicalhealed after 5 years. This finding corroborated the 6- to 9-year 78% microsurgery although only 76% were healed. The difference of 9%success rate reported by Yazdi et al (12). This long-term prognosis is between these 2 outcome measures was lower than the 20% differencepoorer than the 73% to 92% reported in the short-term after using (94% and 74%, respectively) reported in the Toronto Study (15).Retroplast (16, 31–35), suggesting regression over time. Indeed, of Nevertheless, these findings underlined the frequent absence of clinicalthe 85% Retroplast-treated teeth that were healed after 1 year in our signs and symptoms associated with post-treatment apical periodontitisprevious study (16), over 9% showed regression after 5 years in the (4, 14, 15) and the importance of radiographic examination tocurrent study, whereas 6% regression was reported in another long- comprehensively assess the outcome of treatment. According toterm study (12). Although conceptually apical capping with a dentin- Barone et al (15), patients weighing different treatment alternativesbonded material is expected to seal potential bacterial pathways for teeth with post-treatment apical periodontitis should be informedTABLE 3. Radiographic Classification of Healing at 5 Years (n = 170) after Apical Microsurgery Related to Classification at 1 Year and the Root-end FillingMaterial Used Healing classification Root-end filling material 1 year 5 years SuperEBA ProRoot MTA Retroplast Category n* Category n %S n %S n %S n %S Complete 130 Complete 114 87.7 28 84.8 31 91.2 55 87.3 Incomplete 2 1.5 1 3.0 1 2.9 0 – Uncertain 7 5.4 3 9.1 1 2.9 3 4.8 Unsatisfactory 7 5.4 1 3.0 1 2.9 5 7.9 Subtotal 33 34 63 Incomplete 11 Complete 2 18.2 1 20.0 1 20.0 0 – Incomplete 7 63.6 3 60.0 3 60.0 1 100 Uncertain 1 9.1 1 20.0 0 – 0 – Unsatisfactory 1 9.1 0 – 1 20.0 0 – Subtotal 5 5 1 Uncertain 22 Complete 3 13.6 1 12.5 1 33.3 1 9.1 Incomplete 1 4.6 0 – 1 33.3 0 – Uncertain 10 45.5 3 37.5 1 33.3 6 54.5 Unsatisfactory 8 36.4 4 50.0 0 – 4 36.4 Subtotal 8 3 11 Unsatisfactory 7 Complete 1 14.3 0 – 0 – 1 50.0 Incomplete 0 – 0 – 0 – 0 – Uncertain 0 – 0 – 0 – 0 – Unsatisfactory 6 85.7 3 100 2 100 1 50.0 Subtotal 3 2 2 Total (n) 170 Complete 120 70.6 30 61.2 33 75.0 57 74.0 Incomplete 10 5.9 4 8.2 5 11.4 1 1.3 Uncertain 18 10.6 7 14.3 2 4.5 9 11.7 Unsatisfactory 22 12.9 8 16.3 4 9.1 10 13.0Total of healed cases after 5 years (129/170, Table 1) differs from the total number of cases with complete and incomplete radiographic healing after 5 years (130/170) because 1 case with completeradiographic healing presented with clinical symptoms.%S, proportion of subtotal filled with given material.Healing classification according to Molven et al.17*n excludes 21 subjects lost to follow-up.JOE — Volume 38, Number 5, May 2012 5-Year Outcome of Apical Surgery 577
  9. 9. Clinical ResearchTABLE 4. The Final Logistic Regression Model Identifying 2 Significant Several patient-, tooth-, and treatment-related variables (ie,Predictors of the Healed Outcome 5 Years after Apical Microsurgery smoking, tooth location, lesion size, 1-sided interproximal bone loss, Odds Confidence P antibiotic coverage, and postoperative healing course) were associated Variable ratio interval value with 5-year healed rate differentials of 10% or greater, which are considered clinically meaningful. According to the multivariate analysis, Crestal bone level* (0 = >3 mm,1 = #3 mm) 5.10 1.67-16.21 .017 these variables did not significantly impact the outcome. The lack of Root-end filling significance might have been caused by uneven distributions of subsets (0 = SuperEBA, 7.65 2.60-25.27 .003 of the cohort across each variable, but it might also suggest that 1 = ProRoot MTA) the differences might be random.All other variables listed in Table 1 were rejected in the series of logistic regression modelsconstructed. Conclusions*Measured on radiographs from the cementoenamel junction or, if not visible, from the margin of a This study provided a high level (1b) of evidence for the 5-yearcrown or filling. prognosis after apical microsurgery, with 76% of the teeth healed. The healed rate was 8% lower than the reported 1-year rate for the same cohort, with 16 teeth (12% of the cohort) regressing and 5 teethabout the high probability of retaining asymptomatic function 5 years (3% of the cohort) progressing from the first to fifth year after treat-after apical microsurgery even if radiographs do not suggest the teeth ment. One tooth-related outcome predictor was identified: the healedto be healed. Such information can assist the patients, especially rate was higher when the mesial and distal interproximal bone levelthose experiencing preoperative symptoms, in relating the pro- was #3 mm from the cementoenamel junction (or restorationjected outcomes to their individual values and in setting specific margin). Another treatment-related outcome predictor was supportedgoals they hope to achieve by having the teeth treated by apical micro- by a lower level of evidence (2b): the healed rate was higher for root-surgery. end fillings with ProRoot MTA (86%) than with SuperEBA (67%). There As highlighted earlier, this longitudinal study provided insight is an urgent need for additional prospective studies to augment theinto the dynamics of healing and its regression beyond the first evidence for the long-term prognosis of apical microsurgery and toyear after apical microsurgery, suggesting overestimation of the prog- assess the root-end filling materials and other intervention aspects ofnosis by short-term assessment. In previous longitudinal studies in apical microsurgery at high-level evidence.which treatment was not consistent with apical microsurgery (6),the 1-year assessment predicted the 5-year prognosis with an accu-racy of 91% (7) and 95% (8), which is similar to the 95% predictive Acknowledgmentsaccuracy reported in a current 6- to 9-year study (12) and the 90% The authors thank Dr. J€rg H€sler and Kasper Stucki, Institute u upredictive accuracy reported herein. In the longer-term, regression of Mathematical Statistics and Actuarial Science, University offrom healed to nonhealed in some teeth (16 in the present study) Bern, Bern, Switzerland, for the statistical analysis.is partially offset by continued healing of fewer teeth (5 in the present The authors deny any conflicts of interest related to this study.study) that are not healed in the short-term. Thus, the short-termoutcomes of apical microsurgery cannot be taken as reportedbecause they overestimate the long-term prognosis, but they can Referencesbe extrapolated to project the long-term prognosis at roughly 90% 1. Eriksen HM, Kirkevang L-L, Petersson K. Endodontic epidemiology and treatment outcome: general considerations. Endod Topics 2002;2:1–9.to 95%. 2. Friedman S. Considerations and concepts of case selection in the management of Although the long-term prognosis can be projected from short- post-treatment endodontic disease (treatment failure). 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